Fused Metal Battery Seal with Breakable Vent for Pressure Relief
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Solution Overview
Problem
Secondary batteries, particularly those made of stainless steel (SUS) or steel with a plating layer, face safety concerns due to potential expansion under internal pressure, which can lead to structural integrity issues.
Innovation Solution
Incorporating a vent with low coupling force between the case cover and case body due to fusion in the sealed portion of the battery, allowing the vent to easily break and release pressure if the battery expands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the case is sealed by fusion to ensure structural integrity, then the sealing strength is improved, but the vent becomes difficult to break under internal pressure
Solution Approach 1:
The sealed portion has non-uniform fusion characteristics: the main sealed regions have strong coupling force for structural integrity, while the vent region has intentionally reduced coupling force to enable easy breaking under pressure. This local differentiation resolves the contradiction between strong sealing and reliable pressure release.
Solution Approach 2:
The vent is pre-formed with reduced fusion coupling force during the sealing process, preparing it in advance to break easily when internal pressure builds up. This preliminary preparation ensures the vent can reliably release pressure without requiring additional mechanisms.
2Strength
If the case is made of stainless steel or steel with plating layer, then the structural strength is improved, but the expansion resistance under internal pressure worsens
Solution Approach 1:
The case structure is segmented into a strong metal body for structural support and a separate sealed portion with controlled fusion characteristics that can yield under pressure. This segmentation allows the metal case to provide strength while the sealed portion manages pressure expansion through controlled breaking at the vent.
Solution Approach 2:
The potential harmful expansion of the metal case under internal pressure is converted into a beneficial safety mechanism: the pressure causes the vent to break, releasing the pressure before it can cause dangerous expansion or rupture of the entire battery structure.
3Stability of the object's composition
If the vent is positioned in the center of the sealed portion, then the pressure distribution is improved, but the coupling force between case cover and case base worsens
Solution Approach 1:
The vent region in the center of the sealed portion has locally reduced fusion coupling force compared to the surrounding sealed areas. This local quality differentiation enables the vent to break easily for pressure release while the surrounding areas maintain strong coupling for structural integrity and proper pressure distribution.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances safety by facilitating the release of internal pressure, thereby preventing structural damage and potential hazards associated with battery expansion.
Implementation Method 1
the case includes a sealed portion sealed by fusion on at least three sides of the case
Implementation Method 2
the vent is easily broken if a secondary battery made of stainless steel (SUS) or steel with a plating layer formed on the surface thereof is expanded by internal pressure
Data Source
AI summary
A secondary battery having a structure in which a vent having a low coupling force due to fusion is provided in a sealed portion such that the vent is easily broken if a secondary battery made of stainless steel (SUS) or steel with a plating layer formed on the surface thereof is expanded by internal pressure, thereby improving safety. The secondary battery includes an electrode assembly having a positive electrode plate, a negative electrode plate, and a separator between the positive electrode plate and the negative electrode plate and a case configured to receive the electrode assembly. The case includes a metal layer and a sealed portion sealed by fusion on at least three sides. The sealed portion includes at least one vent.